The purpose of this experimental investigation is to examine the phase separation characteristics of a two-phase gas-liquid mixture into a series of branch tubes from a header pipe. This kind of flow is encountered at, for example, an air conditioner. Three parallel branches were attached vertically downward in right angles to the horizontal inlet main tube (14 mm inside dia.) and 50 mm apart from each other. In the present experiment the flow rate of both phases in branch tubes (4 mm inside dia.) and static pressure distributions were measured. The flow pattern in the main tube is mainly slug flow. It is found that there was a maldistribution of air and water among branches.